Chapter 8 Hematologic Cell Markers Objectives At the

Chapter 8 Hematologic Cell Markers

Objectives At the end of this chapter, the student shall be able to: q Explain the cellular markers that can be used for the diagnosis of hematologic abnormalities q Differentiate the Types of immunological marker q Methods of immunological marker

Surface Markers • Proteins present on the cell membrane that can be detected with immunologic reagents • Different proteins are expressed at different stages of maturation; – some are present early in development while others do not appear until much later. – Still other proteins may appear, and then disappear, only to reappear at a later stage of development. – This unique expression of proteins enables them to be used as markers of both cell lineage and maturation stage.

Selected Cell Markers • Blasts: express CD 34, CD 117, CD 133, and/or Td. T • Promyelocytes: express CD 117, CD 15, CD 33 and CD 13 without CD 34 or HLA-DR • Promonocytes: express HLA-DR, CD 64 and low CD 13 without CD 34 or CD 14 • Cytoplasmic Immunoglobulin is the only cytoplasmic marker that is routinely evaluated in the workup of acute leukemia of B cell origin

Terminal Deoxynucleotidyl Transferase Test (Td. T) q Td. T is a DNA polymerase present in lymphocytic cells q Td. T is a nuclear enzyme marker for primitive lymphoid cells. q High levels are found in the majority of lymphoblastic leukemias, but not in most cases of AML. Thus, it is a useful study to differentiate between ALL and AML q There may be low levels in about 10% of AML cases Principle: q Rabbit antibody to Td. T is incubated with cold methanolfixed cells. Then FITC - labeled goat anti-rabbit antibody is incubated with the cells q If Td. T is present in the cells, the positive cells will appear fluorescent

Interpretation of Td. T assay § Majority of patients with T and null cell ALL and lymphoma will have a positive Td. T. Also, patients with pre-B ALL, 50% of patients with acute undifferentiated leukemia, and 30% of patients in CML Blast Crisis will also have Td. T activity § Approximately 5% of patients with AML will have Td. T activity § In summary, Td. T is a marker for primitive lymphoid cells

Number mature myeloid MPD MDS Aplastic anemia CML PV ET CIMF Number mature lymphoid Immature CD 34 Lymphoma Leukemia/ lymphoma Non. Hodgkin Myeloid B-cell CD 19, 20 T-cell CD 2, 3, 5, 7 4/8 Figure: Markers used for the diagnosis and differentiation of hematologic disorders Lymphoid Td. T CD 13, 33, MPO B-cell CD 19, 20+/- T-cell CD 2, 3, 5, 7 4/8

Review Questions 1. Define cell markers 2. State the purpose of using cell markers 3. List a minimum of 5 cell markers and their clinical significance